If Oliver Koppell launches a bid against State Senator Jeff Klein, he can expect to hear plenty about former Mayor Michael Bloomberg.

Mr. Koppell, edging ever closer toward declaring his intentions to run against Mr. Klein in the Bronx, has repeatedly blasted the co-majority leader for marshaling a breakaway faction of Democrats that govern the State Senate with the GOP. In Mr. Koppell’s eyes, Mr. Klein has betrayed Democratic and liberal values, but those close to Mr. Klein say Mr. Koppell, a former councilman, assemblyman and attorney general, is the hypocrite.

Mr. Koppell, then a councilman seeking a third term, endorsed Mr. Bloomberg’s controversial 2009 re-election bid. Klein supporters say Mr. Koppell passed on a credible Democratic challenger in Bill Thompson and therefore has little right to say that Mr. Klein turned his back on Democrats.

“There was a credible African-American Democratic challenger in Thompson, someone who could win, and Koppell didn’t endorse him,” one of Mr. Klein’s allies in the Bronx told the Observer. “That’s an issue.” (Mr. Klein’s office didn’t immediately respond to a request for comment.)

While Mr. Koppell has yet to make his bid official, Bronx political observers believe it is increasingly likely he’ll take the plunge against Mr. Klein next week. Mr. Koppell has set an Easter deadline for himself to decide whether he will run, citing the need to ensure he has sufficient support from community, political and labor groups, as well as the Senate Democratic conference.

In addition to his support of Mr. Bloomberg, a Republican-turned-independent, Klein surrogates say Mr. Koppell’s proud backing of a deeply unpopular City Council bill that temporarily overturned the term limits law in 2008 could haunt him in this race. Mr. Koppell introduced the bill and told reporters at the time he did not believe in term limits or referendums that allow the public to vote on policy.

“The public can’t be trusted to make good decisions, Koppell says, pointing to “all the mischief” going on in California, where they outlawed gay marriage and constricted education spending through referenda,” the Norwood Newsreported in 2009.

“Many people are not sophisticated enough to make some of these decisions.” Mr. Koppell told the paper. “That’s why I believe in electing people who spend the better part of their lives working on these issues.”

The term limit vote weighed down former Council Speaker Christine Quinn’s mayoral bid a year ago, but Mr. Koppell does not think his support of Mr. Bloomberg or his steadfast opposition to term limits will be held against him this time around.

“Sixty-four percent of my constituents voted to re-elect me in the [2009] primary, when that was an issue. Eighty percent voted for me in the general election. I’m not concerned,” Mr. Koppell told the Observer in an interview today, acknowledging that abolishing term limits is not a “particularly popular position” in his old district.

On Mr. Bloomberg, Mr. Koppell also did not back away from his decision.

“I never regarded Bloomberg as a Republican. He did run on the Republican line but he is an independent,” he said. “I supported him because I thought he had done a good job overall as mayor and he was likely to be the winning candidate and I felt we could do positive things for the city and community together.”

“I don’t make decisions necessarily on the basis of political consequences,” he added. “I decide what is right as a matter of public policy.”